Coffee making apparatus incorporating metered dispensing

ABSTRACT

A coffee and/or tea dispenser having a cold water reservoir connected to a water heater which is connected in turn to a spray head. Below the head is a container for a bed of coffee grains or tea leaves and below which again is a tank for the infused beverage. Cups of freshly infused coffee or tea can be metered from the tank by a dispensing valve. In order to ensure the head of liquid applied to the valve is within reduced limits the tank is wide and low. The tank is preferably dismountable for easy cleaning and level probes normally protruding into the tank are arranged to be swung out of the tank to assist dismounting. The dispensing valve is preferably formed with a flexible liquid conduit squeezed between three abutments so that the tube is not clamped but rather distorted into a closed state.

This invention relates to coffee and tea making apparatus or brewingapparatus and in particular to apparatus which is capable of dispensinga predetermined volume of beverage, e.g. a cupful, for example uponpayment of a fee.

Vending machines for dispensing both hot and cold beverages upon paymentof a fee are well known. When dispensing hot beverages such as tea orcoffee the majority of known vending machines mix a solid or liquidconcentrate of the desired beverage with a quantity of hot water. Thus,these machines dispense beverages of the type commonly referred to as"instant coffee" or "instant tea" rather than beverages which arefreshly prepared by infusion with tea leaves or ground coffee.

The only commercial apparatus known to the Applicants capable ofdispensing a beverage such as percolated coffee suffers from severaldisadvantages. The apparatus is plumbed in to the water mains and wateris fed directly to a heating apparatus in which the water passes througha spiral passage associated with a thermostatically controlled heatingelement situated above an infuser basket and thereafter the hot waterpasses through ground coffee positioned in the infuser basket and thecoffee liquor is collected in a large volume coffee tank. The coffeetank is maintained at the desired temperature by heating elements. Theapparatus comprises a coin mechanism which actuates a dispensing valveon the coffee tank upon payment of a predetermined fee. The dispensingvalve is positioned in the base of the coffee tank and comprises asolenoid valve having a vertically movable valve member. The coffee tankhas a relatively large volume and there is a considerable pressure headdifferential at the dispensing valve when the levels of coffee withinthe tank are substantially full and substantially empty. Accordingly,the apparatus requires special control means to vary the dispensing timedepending upon the level of coffee within the tank. In absence of suchcontrol mechanism there is a dispensing difference of the order of 20%when volumes are dispensed when the tank is full and the tank issubstantially empty. This known apparatus has encountered problems ofreliability in connection with the dispensing valve and the metering ofuniform volumes of coffee.

It is an object of the present invention to provide improved coffee andtea making or brewing apparatus for dispensing metered volumes ofbeverage.

Therefore according to one embodiment of the invention there is providedcoffee and tea making or brewing apparatus comprising a cold waterreservoir, a conduit from said reservoir extending to the inlet of awater heater to supply cold water thereto, a conduit extending from saidwater heater to a spray head to convey hot water thereto, the spray headbeing mounted above means for supporting a bed of ground coffee, tealeaves or the like, such that hot water exiting the spray head passesthrough said bed into a beverage retaining tank, the beverage retainingtank having an outlet in communication with a dispensing conduit, thedispensing conduit being associated with a dispensing valve which isoperable to allow predetermined volumes of beverage to be dispensed fromthe beverage retaining tank through the dispensing conduit.

The apparatus of the invention is preferably coffee making apparatus andcomprises an infuser basket for supporting a filter paper and groundcoffee. The cold water reservoir, water heater and spray headarrangement are preferably of the type disclosed in British Patent Nos.2 056 266 and 2 059 753. Such an arrangement is particularlyadvantageous since it does not require a water pump, thermostat andsophisticated control apparatus to operate the coffee making cycle.

The beverage retaining tank preferably has a volume in excess of thewater reservoir, more preferably at least three times the volume of thewater reservoir.

The means for operating the dispensing valve is preferably associatedwith a coin mechanism such that dispensing may only occur when apredetermined value of coins have been inserted into the coin mechanism.However, the coin mechanism is not essential and the apparatus maysimply be provided with a switch for dispensing a predetermined volumeof beverage, e.g. a cupful.

Preferably, the beverage retaining tank, dispensing conduit anddispensing valve are arranged such that when the dispensing valve isopen for a predetermined time substantially the same volume of beveragewill be dispensed regardless of the level of liquid in the beverageretaining tank. This may conveniently be achieved by ensuring that thereis not a significant pressure head differential at the dispensing valvebetween the states when the beverage retaining tank is full and empty.

In accordance with a further embodiment of the invention the apparatusincludes one or more movable probes associated with a removable tank forcontaining liquid such that when the tank is removed the probe(s) ismoved clear of the tank.

In accordance with a further embodiment of the invention the apparatuscomprises a flexible dispensing conduit having a dispensing valvecomprising two spaced, fixed members positioned upon one side of theflexible conduit and a movable member positioned on the other side ofthe conduit so that in operation the movable member is urged towards thespace between the fixed members thereby deforming the flexible conduitand closing the bore therein. This arrangement has significantadvantages over a valve employing a simple clamp since it provides aneffective valve and does not cause damage to the flexible conduit.Furthermore, the flexible conduit may be readily removed for cleaningand replacement.

The invention will now be described with reference to the accompanyingdrawings, in which:

FIG. 1 is an isometric view of a coffee making apparatus in accordancewith the invention,

FIG. 2 is a schematic diagram showing the flow of liquid within thecoffee making apparatus of FIG. 1,

FIG. 3 represents a circuit diagram for controlling the coffee makingapparatus in accordance with FIGS. 1 and 2,

FIG. 4 represents a cross-section through a dispensing valve suitablefor use in coffee making apparatus in accordance with the invention, and

FIGS. 5(a) and 5(b) illustrate a pivoting probe suitable for use withcoffee making apparatus in accordance with the invention.

Referring to FIG. 1 the coffee making apparatus comprises a casing orbody 2 having a front panel 4, an infuser basket 6 and a dispensingnozzle 8. Beneath the dispensing nozzle 8 is a drain 10 adapted tosupport a container 11 (shown in FIG. 2) e.g. a cup or mug, into whichthe coffee is to be dispensed.

The front panel 4 comprises four indicator lights 12a to 12c and 112, atotaliser coin display board 100, a coin slot mechanism 16 and rejectcoin aperture 18. The function of the above components will be describedhereinafter.

Referring to FIG. 2 the coffee making apparatus comprises an internalcold water tank or reservoir 20 positioned at its top. The tank 20comprises an inlet 22 through the top of the casing 2 to receive coldwater from a flask or the like. The inlet 22 is provided with a cover 24(see FIG. 1). The water tank 20 is additionally provided with a coldwater inlet 26 in communication with the water mains via an inlet 28.The flow of water to the water tank via the mains is controlled by awater valve 30. Thus, the coffee making apparatus may be plumbed in tothe mains or manually replenished with fresh water.

The cold water tank 20 has an outlet 32 in communication with the inlet34 of a water heater unit 36. Heated water from the water heater unit 36passes via the outlet 38 through a pipe 40 to a spray head 42 positionedabove the coffee infuser basket 6. The basket is lined with a removablefilter paper on which is positioned a bed of ground coffee (not shown).As is conventional, the infuser basket 6 can be lifted out from theapparatus using its handle in order to replace the filter paper andcoffee.

The infuser basket 6 is approximately conical in shape tapering to anoutlet hole 44 positioned above an inlet 46 to a coffee tank 48 so thatcoffee liquor which is formed by hot water passing from the spray head42 through the bed of ground coffee in the infuser basket 6 passes intothe coffee tank 48 for storage prior to dispensing. The coffee tank 48may be provided with heating pads 50 to maintain the coffee at itsdesired temperature. Alternatively, the coffee tank 48 may be providedwith heat insulation means, e.g. vacuum insulation or foam insulation.

The coffee tank 48 has an outlet 52 in communication with a flexibledispensing tube 54 having a dispensing valve 56 to control dispensing ofthe coffee.

The spray head 42 and water heater unit 36 may conveniently be of thetype described in our British Patent Specification Nos. 2 056 266 and 2059 753.

FIG. 3 represents a schematic layout of the control means for the coffeemaking apparatus shown in FIGS. 1 and 2. The numbered components in FIG.3 are as follows:

12a--sold-out light

12b--coffee low light

12c--coffee dispense switch and indicator

14--totaliser board

20--water tank

30--water valve

36--water heater unit

48--coffee tank

50--heat pads

56--dispensing valve

100--totaliser coin display

101--coin mechanism

102--control board

103--infuse button

104--mains cable

105--mains transformer

106--terminal block

107--dispense volume adjuster

108--excess temperature cut-out

109--mains switch

110--automatic/manual switch

111--infuser safety interlock

112--infuser interlock indicator

113--recharge switch

Coffee preparation cycle

Filter paper and ground coffee are introduced into the infuser basket 6which is placed beneath the spray head 42 as shown in FIGS. 1 and 2.Switch 110 is selected for manual or automatic (as shown in FIG. 3)depending upon whether the water reservoir 20 is to be charged manuallyvia the inlet 22 or from the water mains via inlet 26. The infuserbutton 103 is depressed for operation of the coffee making cycle whenswitch 110 is set in the automatic mode.

The presence of water in the water reservoir 20 is detected by a probewhich switches on the water heater unit 36. Cold water flows into thewater heater through the inlet 34 and water flowing through the waterheater is heated by the heating element to its boiling pointirrespective of its temperature at the inlet. Hot water passes from thewater heater via exit 38 and rises through conduit 40 to the spray head42. The conduit 40 is routed such that it includes a portion slightlyabove the water level in the reservoir 20 so that there is no pressurehead from the reservoir forcing the water through the water heater andto the spray head 42. As the water is heated in the water heater unit 36it is expanded and a small amount of steam is generated when the waterreaches its boiling point. The expansion of the water and generation ofsteam causes hot water to rise through conduit 40 setting up anintermittent syphon delivering water into the spray head in a series ofspurts. This has the advantage that the water falling on the bed ofcoffee is always at a consistent temperature at, or just below, boilingpoint which temperature is ideal for the brewing of either tea orcoffee. The water heater does not deliver the hot water in a continualstream but in a series of spurts which is ideal for high coffeeextraction, as the coffee grounds go through a number of flood and soakcycles.

No thermostat is required to operate the system nor is provided althougha high temperature safety cut-out 108 is incorporated in the waterheater to protect the heating element. The heating element in the waterheater is only energised when a probe in the water reservoir 20 detectsthe presence of water. Thus, so long as there is water in the reservoir20 the heater is energised and water will flow from the spray head 42.Once the tank is empty the probe will detect the absence of water andthe heater in the water heater will be switched off to save energy andprevent overheating. The water reservoir also includes an additionalprobe for detecting when the water reservoir is full, which probecontrols the water valve 30 to prevent mains water from entering thereservoir when the reservoir is full.

The water heater unit 36 may conveniently be pivoted to the inside ofthe casing and the associated conduits may be flexible in order to allowready access to the interior of the coffee making apparatus whilst theapparatus is in use. This arrangement is particularly advantageous sincecertain maintenance functions may be performed whilst the machine isfunctioning.

The volume of the water reservoir 20 may be identical to that of thecoffee tank 48 in which case the coffee tank 48 will be fully chargedwith a single coffee making cycle. However, there are certain advantagesin utilising a system in which the coffee tank 48 has a volume in excessof that of the water reservoir 20 such that it will take two, three ormore cycles to fully charge the coffee tank. In the embodiment shown inFIGS. 1 and 2 the water reservoir may conveniently have a volume ofthree pints and the coffee tank may have a volume of nine pints. Thisdifferential in volume capacity between the water reservoir and thecoffee tank allows a smaller infuser basket 6 to be used which isrecharged between cycles. Furthermore, this volume differential allowssome measure of adjustment to the amount of coffee stored in the coffeetank for dispensing thereby preventing large volumes of coffee remainingin the tank for long periods of time. The volume differential alsoallows fresh coffee liquor to be introduced into the coffee tank beforethe tank is completely empty.

The second and subsequent coffee making cycles may be commenced by theprocedure described above. Alternatively, the apparatus can be adjustedto automatically begin a new coffee making cycle when the level ofcoffee in the coffee tank is below a predetermined amount. Rechargeswitch 113 is provided to control the automatic cycle. Upon completionof a coffee making cycle the operator simple recharges the infuserbasket with a new filter paper and ground coffee and actuates rechargeswitch 113. If the level of coffee in the coffee tank is already belowthe predetermined amount the coffee making cycle will begin immediately;if the level of coffee in the coffee tank is above a predeterminedamount the coffee making cycle will commence when the level has beenlowered to the predetermined amount. The coffee tank 48 includes a probefor detecting the desired level; in the embodiment illustrated in FIGS.1 to 3 this probe is also associated with the coffee low light 12bdescribed hereinafter.

The coffee tank 48 is also provided with means for ensuring that thetank cannot be flooded. The tank may be provided with a probe detectingthe level of coffee at the top of the tank which will cause the waterheater 36 to be disconnected when the tank is full thereby ensuring thatno further water is heated and conveyed to the spray head. Additionally,an infuser safety interlock 111 and an infuser interlock indicator 112is incorporated so that if the infuser basket is accidentally removedduring the brewing cycle the water heater 36 will be disconnectedceasing the water cycle and preventing flooding of the machine.

Dispensing cycle

The coffee making apparatus illustrated in FIGS. 1 to 3 may be adjustedto dispense metered volumes of coffee liquor via the dispensing nozzle 8either upon insertion of a predetermined amount of money via coin slot16 and operation of the coffee dispense switch 12c or simply operationof the latter switch. In the payment mode the machine may be adjusted tooperate only upon receiving a predetermined value of money in the formof coins. The coin mechanism 101 may comprise any known mechanism foridentifying coins and has an associated reject mechanism for rejectingany abnormal coins, conveying such coins to the reject aperture 18. Thecoin mechanism is in electrical communication with the totaliser displayboard 14 which comprises a series of lights each associated with aparticular monetary value. Thus, when it is necessary to insert a numberof coins to reach the predetermined price of the coffee the lights onthe totaliser display board will correspond to the total amount of moneyinserted as each coin is entered. When the correct amount of money hasbeen inserted the coffee dispense switch 12c lights up indicating to theuser that it may be operated for the machine to dispense coffee vianozzle 8. When the switch 12c lights up the coin mechanism isautomatically inhibited thereby ensuring that any further money insertedinto the coin slot is returned via the reject mechanism.

Upon operation of the coffee dispense switch 12c the dispensing valve 56is opened for a sufficient time to dispense a predetermined amount ofliquid. In the embodiment shown in FIGS. 1 to 3 the dispensing valve 56is operated by a solenoid which retracts the valve to an open positionfor a predetermined time period, which time period may be adjusted bydispense volume adjuster 107. By suitable positioning of the dispensingvalve 56 in relation to the coffee tank 48 there is no necessity toprovide special provisions for altering the time period for dispensingwhen the coffee tank is substantially full or substantially empty. Thearrangement of the coffee tank and dispensing valve 56 is such that thepressure head `a` at the dispensing valve 56 when the tank is full andthe pressure head `b` at the dispensing valve when the coffee tank isempty is not significantly different so that substantially the sameamount of liquid is dispensed when the dispensing valve is open for thesame time period both when the coffee tank is full and substantiallyempty.

The dispensing valve 56 may comprise any known valve arrangement. It isparticularly convenient to utilise a dispensing tube 54 which isflexible and may simply be clamped or pinched by the valve 56 to preventliquid flow therethrough. Whilst conventional pinch valves which simplycompress the tube in a vice-like grip may be utilised, it has been foundthat such valves may cause damage to the tubing often resulting insevering the flexible tubing. This is believed to be due to the factthat coffee liquor often contains a small amount of solid particleswhich may be trapped between the jaws of the valve during the clampingoperation causing damage to the internal walls of the tubing. Aparticularly convenient dispensing valve is shown in cross-section inFIG. 4. The valve comprises two spaced, fixed members 60,62 and amovable member 64 operated by a solenoid. The flexible dispensing tube54 passes between the fixed and movable members such that when themovable member is in the closed position of the valve the flexible tubeis deformed to completely close the bore in one or more places in asimilar manner to kinking a hose pipe. Thus, the walls of the flexibletube 54 are not clamped between solid jaws of a vice-like valve whichcould cause damage to the tubing.

The coffee making apparatus depicted in FIGS. 1 to 3 additionallycomprises visual display means in the form of a "sold out" light 12aindicating that no coffee remains in the coffee tank 48 and a "coffeelow" light 12b indicating that the level of coffee in the tank 48 islow. The coffee tank 48 is provided with three probes arranged atdifferent levels within the tank. One probe is present to detect whenthe tank is full, which probe is utilised to prevent a further coffeemaking cycle from taking place. A second probe is positioned at someintermediate level, e.g. at the level when the tank is approximately onethird full, which probe causes the "coffee low" light to display andallows initiation of a new coffee making cycle either automatically orby pressing the infuser button 103. A third probe is present in thecoffee tank 48 to detect when the tank is completely empty which probeensures that the coin mechanism will not accept further money and thecoffee dispensing switch will be inoperable.

The front panel 4 of the coffee making apparatus is hinged at one edgein order that it may be opened to remove the coffee tank 48 forcleansing. In order to facilitate cleansing of the coffee tank 48 and toprevent damage to the probes therein, the probes are preferably arrangedsuch that they are automatically moved clear of the coffee tank when thetank is removed from the coffee making apparatus for cleansing.

FIG. 5 of the accompanying drawings illustrates in cross-section anarrangement of pivoting probes in relation to the coffee tank 48. FIG.5a illustrates the coffee tank 48 in the withdrawn position with a probe66 moved clear of the coffee tank 48. The probe 66 is mounted in aninsulating block 68 held in a pivoting member 70 having a substantiallyL-shaped cross-section. The pivoting member 70 is pivoted about an axis72 and is maintained in the position shown in FIG. 5(a) with the proberaised by a compression spring 74 acting on the point 75. Electricalconnectors are provided to the probe at 76.

When the coffee tank 48 is inserted into position within the coffeemaking apparatus, the end of the tank 78 abuts the arm 80 of thepivoting member 70 causing the member to pivot to the position shown inFIG. 5b. During this pivoting action the point of action 75 on thepivoting member 70 of the compression spring 74 moves from one side ofthe axis 72 to the other thereby ensuring that the pivoting member 70 isheld in the position shown in FIG. 5(b) with the probe directed into thecoffee tank 48. Removal of the coffee tank causes end 78 to abut the arm82 of the pivoting member 70 moving the pivoting member to the proberaised position shown in FIG. 5(a).

We claim:
 1. An apparatus for making tea and coffee beverages, saidapparatus including coffee and tea infusing means, a beverage storagetank arranged to receive a beverage formed in said infusing means, saidtank having a bottom outlet, a beverage dispensing outlet positionedbelow said tank outlet, a flexible conduit connected to said tank outletand extending to said beverage dispensing outlet and beverage dispensingcontrol means, said control means comprising a pair of abutments spacedapart and positioned on one side of said flexible conduit, a controlmember normally positioned intermediate said abutments adjacent to andon another side of said flexible conduit and being movable into aportion of the space separating the said two abutments so as thereby tocompress one side of the dispensing conduit against the other side ofthe dispensing conduit and to deflect the said conduit through anarcuate path, and means operable on said control members whereby thedispensing conduit is either fully open or fully closed.
 2. Apparatusaccording to claim 1 wherein said control member operating meanscomprises a controlled solenoid.
 3. Apparatus according to claim 1wherein said control member operating means comprises timing means todetermine the period of time said dispensing conduit is open. 4.Apparatus for making a beverage such as coffee and tea, having a casingincluding:a cold water reservoir having an inlet and an outlet, waterheating means having a water inlet and a water outlet, a first conduitcommunicating between said water heater means inlet and said reservoiroutlet, a spray head, a second conduit communicating between said waterheater means outlet and the spray head, a beverage grain bed supportingmeans, mounted below said spray head so as to receive a water spraytherefrom, a support surface defined by said casing for supporting adispensed-liquid container for receiving dispensed beverage therein, abeverage retaining tank mounted below said bed supporting means andabove said support surface so as to receive infused beverage from saidbed, said tank having a bottom outlet, a flexible conduit communicatingwith said bottom outlet of the tank, said flexible conduit co-operatingwith dispensing valve means which is operable to allow predeterminedvolumes of said beverage to be dispensed through said flexible conduitfrom said tank into a beverage receiving container which has been placedupon said support surface, said dispensing valve means comprising a pairof abutments spaced adjacent one side of the flexible conduit, a controlmember normally positioned intermediate said abutments adjacent to andon the other side of the flexible conduit so as thereby to compress oneside of the said conduit against the other side of the conduit and todeflect the said conduit through an arcuate path, and means operable onsaid control member whereby the dispensing conduit is either fully openor fully closed.
 5. Apparatus as claimed in claim 4 wherein said controlmember operating means comprises a controlled solenoid.
 6. Apparatusaccording to claim 4 wherein said control member operating meanscomprises timing means to determine the period of time said dispensingconduit is open.